Having a first-degree relative with early-onset lung cancer is a greater risk factor for developing lung cancer in blacks than in whites, according to a new report.

“This finding could be the result of a higher degree of underlying susceptibility or aggregation of unmeasured risk factors for lung cancer in black families,” lead author Dr. Michele L. Cote, from Wayne State University in Detroit, and colleagues note.

The new study involved an analysis of data from 7576 first-degree relatives of 692 people who developed lung cancer before 50 years of age and 773 matched “controls” who were free of lung cancer. Approximately one third of the subjects were black.

Among smokers, a history of early-onset lung cancer in a first-degree relative further increased the risk of the malignancy, the investigators report.

By 70 years of age, 17 percent of whites who were relatives of a lung-cancer patient and who smoked and 25 percent of their black counterparts were diagnosed with lung cancer themselves.

After factoring in age, gender, the number of packs smoked, and history of respiratory diseases, blacks with a lung-cancer relative were twice as likely as whites with an affected relative to develop lung cancer.

“These findings are similar to previous reports but are the first to report risks for African American families,” the team points out. They say the data provided here may be useful to relatives of lung cancer patients, to inform them about their own risk of this disease.

SOURCE: Journal of the American Medical Association, June 22/29, 2005.